Monitoring the early-age hydration of self-compacting concrete using ultrasonic p-wave transmission and isothermal calorimetry

作者：Desmet Bram^*; Atitung Kelly Chrysanthe; Sanchez Miguel Angel Abril; Vantomme John; Feys Dimitri; Robeyst Nicolas; Audenaert Katrien; De Schutter Geert; Boel Veerle; Heirman Gert; Cizer Ozlem; Vandewalle Lucie; Van Gemert Dionys

来源：Materials and Structures, 2011, 44(8): 1537-1558.

DOI：10.1617/s11527-011-9717-x

• Self-compacting concrete
• Continuous ultrasonic testing
• p-Wave hydration
• Addition
• Superplasticizer
• Isothermal calorimetry

The early-age hydration (<= 48 h) of a series of self-compacting concretes and corresponding mortars and one traditionally vibrated concrete and mortar is monitored in a continuous way using ultrasonic testing and isothermal calorimetry. The mixtures differ in type of mineral addition, superplasticizer, cement, cement-to-powder ratio and water-to-powder ratio. The influence of these different mixture compositions on the kinetics of the hydration during the first days of the hydration is characterized by the heat production rate q and the evolution of the p-wave velocity, which is a consequence of the microstructural changes. The variations in the acceleration caused by mineral additions and the deceleration caused by superplasticizers lead to a significantly different behavior. Separating the impact of each of the affecting factors is not always possible due to their combined actions. The nature of the acceleration due to limestone additions and the deceleration caused by polycarboxylate ether superplasticizers can be distinguished clearly, but cannot be quantified. The correlation between the ultrasonic and isothermal calorimetric results is investigated based on parameters related to the start and the end of the setting and reveals the meaningfulness of these parameters when assessing the hydration of self-compacting mixtures with continuous ultrasonic techniques.